Dear All,

I installed Exchange 2013 with POP3 services enabled. Now i found the pop3 issue performance when send/receive with attachment over 300 kb always failed. If the attachment less 300 kb, no problem. This issue occour in bandwidth less than 512 kbps. Is there limitation for Exchange server with POP3 enabled especialy for attachment size?

Please advices.

Thanks,

IH

Hi,

Email applications that use POP3 and IMAP4 rely on the SMTP protocol to send messages. The connector for receiving email submissions from client applications that use POP3 or IMAP4 is created automatically upon installation of Exchange. So I suggest to check the max size limit on receive/send connector, by default its 35M.

Get-sendconnector | fl MaxMessageSize

Get-receiveconnector | fl MaxMessageSize

Check the Maximum attachment size in Transport rules

Get-transportrule | fl AttachmentSizeOver,MessageSizeOver

We can also use EMC to check POP3 connection limits

1. In the EAC, navigate to Servers > Servers.
2. In the list of servers, select the Client Access server, and then click Edit  
3. On the server properties page, click POP3.
4. Scroll down and click More options.
5. Under Connection limits, use the following settings:

• Maximum connections   
• Maximum connections from a single IP address   
• Maximum connections from a single user   
• Maximum command size (bytes)   specifies the maximum size of a single command. The default size is 512. The possible values are from 40 through 1,024.

I suggest to increase the Max command size to check this issue.

Best Regards.